Electrically controlled shutter for photographic cameras

ABSTRACT

An electrically controlled shutter for photographic cameras comprising a magnet lever for operating a closing blade locking lever, a sectoral lever for delaying the rotary movement of said magnet lever, a bulb exposure lever engageable with said sectoral lever, and a changeover cam for switching the operative positions of said sectoral lever within the latter&#39;&#39;s scope of movement; and being operative so that, when the power source battery has become consumed and no longer usable or when a bulb exposure performance is required, the shutter function can then be controlled mechanically to obtain a proper exposure time.

United States Paten [191 Hayami et al.

[ Oct. 9, 1973 ELECTRICALLY CONTROLLED SHUTTER FOR PHOTOGRAPHIC CAMERASI [75] Inventors: Tadao Hayami; Atsutada Nakatani;

Munetaka Shimizu, all of Tokyo, Japan [73] Assignee: Kabushiki KaishaKoparu, Tokyo,

22 Filed: Jan. 25,197;

[21] App]. No.: 220,638

I [30] Foreign Application Priority Data Feb. 5, 1971 Japan 46/4610 [52]1.1.8, Cl. 95/53 EB [51] Int. Cl. G031! 9/08 [58] Field of Search 95/10CT, 10 C, 53 EA, 95/53 EB, 11.5 R

[5 6] References Cited UNITED STATES PATENTS 3,650,193 3/1972 MunetakaShimiyu 95/10 CT X 3,638,544 2/1972 Kiyoshi Kitai 95/10 CT PrimaryExaminer-Joseph F. Peters, Jr. Attorney-Cushman, Darby & Cushman [5 7]ABSTRACT An electrically controlled shutter for photographic camerascomprising a magnet lever for operating a closing blade locking lever, asectoral lever for delaying the rotary movement of said magnet lever, abulb exposure lever engageable with said sectoral lever, and achangeover cam for switching the operative positions of said sectorallever within the latters scope of movement; and being operative so that,when the power source battery has become consumed and no longer usableor when a bulb exposure performance is required, the shutter functioncan then be controlled mechanically to obtain a proper exposure time.

3 Claims, 11 Drawing Figure ELECTRICALLY CONTROLLED SHUTTER FORlPlIilOTOGRAPIIIC CAMERAS BACKGROUND OF THE INVENTION a. Field of theInvention The present invention pertains to an electric shutter arrangedso that the exposure time can be controlled by a CR delay circuit. Moreparticularly, the invention relates to an electric shutter arranged sothat, when the power source battery has become dissipated to anunuseable extent, the exposure time can then be controlled also bymechanical means. 7 b. Description of the Prior Art There are knownvarious kinds of electric shutters comprising a C-R delay circuit formedwith a photoconductive element and a capacitor, a transistor adapted tobe controlled of its on-off actions by said C-R delay circuit, anelectromagnet adapted to be controlled of its energization time by theon-off actions of said transistor, and shutter blades adapted to becontrolled of their opening and closing movements by said electromagnet.However, such a known electric shutter is of the incidental that, incase the voltage of the power source battery has dropped to a levelbelow the required value, the delay time which is determined by the C-Rdelay circuit, i.e., the exposure time which should correspond to thebrightness of the object to be photographed fails to be correct andexact. In an extreme case, the shutter blades would be held open andwould become unclosable. Accordingly, a conventional camera equippedwith an electric shutter had the inconvenience that the camera itselfbecame practically unuseable whenever the power source battery becamedissipated and when its voltage dropped below the required value or incase the voltage of the battery temporarily dropped below the requiredlevel at a very cold place.

When a bulb exposure is performed by the use of such an electric shutteras described above, the exposure time control circuit is kept in itsactuated state for a relatively long period. Hence, there arises anotherdrawback that the power source battery is severely consumed, and thisresults in a shortened service life of the battery.

SUMMARY OF THE INVENTION It is, therefore, an object of the presentinvention to provide an electric shutter arranged so that, when thepower source battery has become dissipated to a practically unuseableextent due to its consumption, the shutter mechanism can be controlledto obtain a proper exposure time by mechanical means by operating only asingle changeover member.

Another object of the present invention is to provide an electricshutter which permits bulb exposures to be performed mechanically byoperating said single changeover member.

Other objects and attendant advantages of the present invention willbecome apparent by reading the following detailed statement of anembodiment when taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a plan view showing themechanism of the essential parts of the electric shutter according tothe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, the memberindicated by the reference numeral 1 represents an opening blade lockinglever pivotably mounted on a shaft 2 and urged to rotate clockwise by aspring 3 and provided with an arm la and a bent portion llb for holdingan opening blade not shown in its cocked state. Numeral 4 represents aclosing blade locking lever pivotably mounted on a shaft 5 and urged torotate clockwise by a spring 6 and provided with a pin 4a and a bentportion 4b for holding a closing blade not shown in its cocked state.Numeral 7 represents a starter member pivotably mounted on a shaft 8 andurged to rotate counter-clockwise by a spring 9 and provided with a camportion 7a, a cam portion 7b for being contacted by the end portion ofthe arm Ia of the opening blade locking lever 11, and an engagingportion 7c. Numeral 10 represents a changeover cam pivotably mounted ona shaft Ill and provided with cam portions 10a and 10b and assigned tocontrol the opening and closing actions of the power switch of a knownexposure time control circuit not shown. Numeral 12 represents asectoral lever pivotably mounted on a shaft 113 and urged to rotateclockwise by a spring 14 and provided with a pin 12a contacting said camportion 10a, another pin 12b and a gear portion ll2c. Numeral 15represents a fly wheel pivotably mounted on a shaft 16 and provided witha gear 15a meshing with said gear portion 12. Numeral 17 represents astarter locking lever pivotably mounted on a shaft 18 and urged torotate clockwise by a spring 19 and limited of its clockwise rotation bya stopper 20 and provided with an ann 17a engageable with the engagingportion 70 of the starter member 7. Numeral 21 represents a magnet leverpivotably mounted on a shaft 22 and urged to rotate clockwise by aspring 23 and provided at one end with a pole-contacting portion 21aadapted to be attracted to a magnet 30 and with an arm 21b at the otherend. Numeral 24 represents a holding lever pivotably mounted on saidshaft 22 and urged to rotate clockwise relative to the magnet lever 21by a spring 25 and provided with an arm 24a contacting saidpole-contacting portion 21a and a pin 24b contacting said cam portion7a. Numeral 26 represents a bulb exposure lever pivotably mounted on theshaft 22 and urged to rotate counter-clockwise by a spring 27 andprovided with a pin 26a contacting the changeover cam 10, a bent portion26b and an arm 26c. Numeral 28 represents a release lever movable in thedirections A and B and normally pulled in the direction B by a spring 29and adapted to be pulled downwardly in the direction A against the forceof the spring 29 interlockingly with the release operation of thecamera, so as to be actuated to cause, via an interlocking lever notshown, the starter locking lever 117 to rotate counterclockwise. Numeral30 represents an electromagnet controlled of its energization time bythe aforesaid known exposure time control circuit.

Description will hereunder be directed to the actions of the respectiveparts in the arrangement described above.

The drawing shows the state of the electric shutter in which it is setto be suitable for a bulb exposure performance and also in which theshutter is cocked. The respective changeover operations in the twoinstances for controlling the exposure time, one by mechanical means andthe other by electric means, both from the illustrated state of theshutter are effected by manually operating the changeover cam 10. Morespecifically, the cam is rotated clockwise by the manual operation fromthe illustrated state to set only the pin 26a so as to contact the camportion 10b. Whereby, the shutter is set so that the exposure time iscontrolled by mechanical means. On the other hand, by bringing the pin26a as well as the pin 120 into contact with the cam portion 10b, theshutter is set so that the exposure time is controlled electrically.

Description will next be directed first to an instance wherein only thepin 26a is brought into contact with the cam portion 10b, or in otherwords an instance wherein the exposure time is controlled by mechanicalmeans. In this instance, the power switch of the exposure time controlcircuit not shown is held in its open state by the changeover cam 10. Inthis state, let us assume that the release lever 28 is depressed.Whereupon, the starter locking lever 17 is rotated counterclockwise tobe relieved of its engagement with the engaging portion 7c, and therebythe starter member 7 is rotated counter-clockwise. As a directconsequence, the opening blade locking lever l is caused to rotatecounter-clockwise by the cam portion 7b so that the shutter is opened.This action is followed by the counter-clockwise rotation of the holdinglever 24 caused by the cam 7a. This lever 24 imparts the magnet lever 21a counter-clockwise movement by the spring 25. As a result, the arm 21bof this magnet lever 21 pushes the pin 12b of the sectoral lever 12.Accordingly, the arm 21b of the magnet lever 21 is rotatedcounter-clockwise while being reduced in its speed by both the sectorallever 12 and the inertial resistance exerted by the fly wheel 15 meshingwith this lever 12. As a consequence, the arm 21b of the magnet lever 21pushes the pin 4a to rotate the closing blade locking lever 4counterclockwise, and with this the exposure completes. In thisinstance, the exposure time can be adjusted by the amount of rotation ofthe sectoral lever 12, i.e., by the position of the pin 12a at which itcontacts a inclined face 100 of the changeover cam 10.

The cocking operation of the shutter is performed by manipulating thewinding mechanism not shown of the camera, or more specifically, thismanipulation is accompanied by a clockwise rotation of the startermember 7 on the one hand, which brings its engaging portion 7c intoengagement with the starter locking lever 17, and also simultaneouslyaccompanied on the other hand by the cocking of the shutter opening andclosing action driving mechanism not shown to cause a part of thisdriving mechanism to be locked by the opening blade locking lever l andalso by the closing blade locking lever 4, respectively.

Next, description will be made on an instance wherein both of the pin26a and the pin 12a are brought into contact with the cam portion 10b,or in other words an instance wherein the exposure time is controlled byelectric means. In the manner as stated previously, the cam portion 7aof the starter member 7 rotates the holding lever 24 counter-clockwise.whereupon, due to the changeover action of the changeover cam 10, thepower switch which has been rendered to the state of being able to closeis closed, so that the exposure time control circuit not shown isrendered operative. The electromagnet 30 which is energized at the sametime therewith attracts the magnet lever 21 and holds it thereto. At theend of the lapse of a predetermined exposure time which is the matter ofa second or so, the electromagnet 30 releases the magnet lever 21 tocomplete the exposure as explained previously. In this mode ofoperation, the sectoral lever 12 is located at a position in which ithas been rotated counter-clockwise by the cam portion 10b. Therefore,this sectoral lever 12 has nothing to do with the counter-clockwisemovement of the magnet lever 21.

Next, description will be made on an instance wherein both of the pin26a and the pin 12a are brought into contact with the cam portion 100,or in other words an instance wherein the shutter is set to the bulbexposure state.

In the illustrated state of the shutter, let us assume that the releaselever 28 is depressed. whereupon, after this release lever 28 hasentered the region of action of the bent portion 26b of the bulbexposure lever 26, the starter locking lever 17 is actuated so that thestarter member 7 rotates counter-clockwise, eventually urging the magnetlever 21 to rotate counter-clockwise by the action of the spring 25. Atthis moment, however, the pin 12a is locked by the arm 261: of the bulbexposure lever 26. Accordingly, the magnet lever 21 is prevented frommaking a counter-clockwise rotation via the sectoral lever 12. As aresult, the closing blade locking lever 4 remains inoperative. Thus, byrelieving the release lever 28 of its depression to have this lever 28resume its initial position by the action of the spring 29, the bulbexposure lever 26 is caused to rotate clockwise by the action of thespring 27 to relieve the pin 12a of its locking state. As a consequence,the magnet lever 21 rotates counter-clockwise, causing the closing bladelocking lever 4 to rotate counter-clockwise to close the shutter.Accordingly, the bulb exposure is effected mechanically without the useof the exposure time control circuit.

We claim:

1. An electric shutter for photographic camera comprising:

an electromagnet controlled of its energization time,

a magnet lever positioned adjacent to said electromagnet and adapted tobe attracted to said electromagnet and held thereto continuously so longas said electromagnet is being energized,

a holding lever positioned to be engageable with said magnet lever andadapted to be rotated by said magnet lever upon de-energization of saidelectromagnet to start shutter closing movement,

a sectoral lever positioned to be engageable with said magnet lever andcapable of delaying the rotary movement of said magnet lever, and

a changeover cam positioned to be engageable with said sectoral leverand capable of moving said sectoral lever into and out of engagementwith said magnet lever.

2. An electric shutter according to claim 1, in which said changeovercam has a cam face for altering interlockingly the position ofengagement of said magnet lever with said sectoral lever as saidsectoral lever is moved into engagement with said magnet lever.

3. An electric shutter according to claim 1, in which said electricshutter further comprises a bulb exposure lever positioned to beengageable with said changeover cam for moving said sectoral lever intoengagement with said magnet lever when said changeover cam has been setto the bulb exposure position and for enabling said bulb exposure leverto lock said sectoral lever during the shutter release operation.

a: k a: a

1. An electric shutter for photographic camera comprising: anelectromagnet controlled of its energization time, a magnet leverpositioned adjacent to said electromagnet and adapted to be attracted tosaid electromagnet and held thereto continuously so long as saidelectromagnet is being energized, a holding lever positioned to beengageable with said magnet lever and adapted to be rotated by saidmagnet lever upon deenergization of said electromagnet to start shutterclosing movement, a sectoral lever positioned to be engageable with saidmagnet lever and capable of delaying the rotary movement of said magnetlever, and a changeover cam positioned to be engageable with saidsectoral lever and capable of moving said sectoral lever into and out ofengagement with said magnet lever.
 2. An electric shutter according toclaim 1, in which said changeover cam has a cam face for alteringinterlockingly the position of engagement of said magnet lever with saidsectoral lever as said sectoral lever is moved into engagement with saidmagnet lever.
 3. An electric shutter according to claim 1, in which saidelectric shutter further comprises a bulb exposure lever positioned tobe engageable with said changeover cam for moving said sectoral leverinto engagement with said magnet lever when said changeover cam has beenset to the bulb exposure position and for enabling said bulb exposurelever to lock said sectoral lever during the shutter release operation.